1. Field of the Invention
The present invention relates to a method for improving inkjet performance, and more particularly, to a method for improving the morphology of drops ejected from an inkjet dispenser by shifting the operation region of the inkjet dispenser to a dwell time corresponding to the third harmonic.
2. Discussion of the Related Art
In an increasingly large number of industries, the ability to accurately and repeatedly deposit nanogram quantities of a given substance is critical to the development of new technologies. This is largely driven by a move towards micro- and nano-scale products that require extremely accurate processing steps. Many applications require repeatable deposition of nano- or picoliter quantities of solutions to precise locations on a target. This is particularly true in the manufacturing of many medical devices where the amount and location of drug loading should preferably be controlled to very precise specifications. In such cases, drop-on-demand inkjet technology is an attractive choice as it addresses the needs for both accurate targeting and repeatable droplet ejection.
As set forth above, drop-on-drop demand inkjet technology is an attractive choice for applications where accurate targeting and repeatable droplet ejection is critical. The normal mode of operation for inkjet dispensers is in the dwell region corresponding to the first harmonic and has a number of potential drawbacks including ligament like drop shapes with satellites and amorphous shaped drops as opposed to predictable round shaped drops. Other than the impact on targeting, operation in this dwell region also makes quantitation by optical techniques extremely challenging.
Accordingly, there exists a need for overcoming the disadvantages associated with the current technology by developing a method of shifting the operation of the inkjet dispenser to higher dwell regions or times corresponding to higher harmonic or resonance points, specifically, the dwell region corresponding to the third harmonic, where round drops may be obtained over a wide range of voltages, as well as a method for identifying any transition regions that may lead to high variability in drop mass over time.